The present invention relates generally to prosthetic devices, and more particularly, to a prosthetic knee chassis featuring adjustable couplings provided on or with the proximal and/or distal segments thereof.
As shown in FIG. 1, a conventional prosthetic limb 10 for a transfemoral amputee will include a prosthetic limb socket 12 for receiving the wearer's residual limb, a knee-joint assembly 14, a first pylon component 16 between the prosthetic limb socket 12 and the knee-joint assembly 14, interconnection components 18 for coupling the first pylon 18 to the prosthetic limb socket 12, interconnection components 20 for coupling the first pylon 16 to the knee-joint assembly 14, a prosthetic ankle/foot assembly 22, a second pylon 24 between the knee-joint assembly 14 and the ankle/foot assembly 22, interconnection components 26 for coupling the second pylon 24 to the knee-joint assembly 14 and interconnection components 28 for coupling the second pylon 24 to the ankle-foot assembly 22. The interconnection components 20 may include a conventional pyramid connector 30 mounted to a proximal end 32 of a proximal segment 34 of the knee-joint assembly 14 and a conventional pyramid receiver 36 mounted to a distal end of the first pylon 16. Interconnection components 26 may include a conventional pyramid coupling 30 mounted to a distal end surface 38 of a distal segment 40 of the knee-joint assembly 14 and a conventional pyramid receiver 36 mounted to a proximal end of the second pylon 24. If the prosthetist wishes to provide rotational and/or lateral adjustability with respect to the first pylon 16 and the proximal segment 34 of the knee-joint assembly or wishes to provide rotational and/or lateral adjustability between the distal segment 40 of the knee-joint assembly and the second pylon 24, the prosthetist may wish to replace one or both of the conventional pyramid plates 30 with the adjustable pyramidal link plate assemblies as disclosed in U.S. Pat. Nos. 6,033,440 and 6,231,618. Such adjustable pyramidal link plate assemblies are commercially available from Prosthetic Design, Inc. as component nos. PYR-SL, PYR-SL-R, PYR-TL-SL, PYR-TL-SL-R, Stealth360, and PYR-TL-R.
If a patient has an amputation that occurs at the femoral epicondyles (hereinafter referred to as “knee disarticulation”) or has a very long residual limb, then difficulties may arise fitting the aforementioned components of the upright assembly between the distal end of the socket 12 and the floor. Furthermore, the knee center K on the prosthesis 10 may move distally with the addition of components between the distal end of the socket 12 and the knee-joint assembly 14. These components may be of paramount importance when it comes to the static and dynamic alignment of the prosthesis. The above-mentioned adjustable pyramidal link plate components, in some cases, may add length of the prosthesis so as to offset the knee center of the prosthesis K from the sound side knee center, which may adversely affect the patient's gait pattern. Accordingly, it is desired to provide the adjustability that the prior art adjustable pyramidal link plate assemblies provide (rotational and/or lateral adjustment capabilities) while maintaining a proper knee center with respect to knee disarticulations and long AK amputations.